This invention relates to surgical cutting apparatus and methods for cutting tissue, and more particularly to a surgical saw blade that directs irrigating fluid at a cutting site while a cutting operation is being performed.
Saw blades for cutting tissue such as bone are well known and exemplified in U.S. Pat. Nos. 3,905,105; 3,905,374; 3,952,412; 4,513,742 and 4,584,999.
Generally, in any bone cutting operation there is a buildup of temperature at the cutting area or cutting site due to friction between the blade and the bone. If bone cutting temperatures increase beyond a predetermined level there is a possibility of bone necrosis, and a consequential prolongation of the healing process.
In some instances it is necessary to slow down the cutting procedure in order to control the buildup of cutting temperatures. However, such slowdowns, which result in extended operation times, can be discomforting to a patient and a strain on the surgeon.
The problem of heat buildup during a tissue cutting operation can be alleviated by dispersing fluid at the cutting site proximate the cutting blade. For example, U.S. Pat. No. 4,511,334 shows a dental cutting instrument for cutting slots into the jaw prior to installation of a dental prosthesis. The dental cutting instrument includes a circular saw blade having radial bores that extend from a hollow central drive shaft to the periphery of the blade, which contains cutting teeth. Coolant is introduced into the hollow drive shaft and dispersed through the radial bores of the blade to the cutting teeth.
In order for the dental cutting blade to adequately accommodate the bores, the blade is formed with radial thicknesses at the area of the bores. A blade of this type is relatively expensive to manufacture because the bores which conduct fluid from the hollow central drive shaft to the blade periphery must be precisely drilled. Of further concern is that the end of the bores which open at the cutting teeth are relatively small and are thus likely to become clogged by material removed during the cutting operation.
Another embodiment of U.S. Pat. No. 4,511,334 includes a cutting blade having radial slots formed in a face of the circular blade. A fluid hose accessory directs fluid into each of the slots sequentially as the blade rotates past the delivery end of the fluid hose, which is positioned slightly above the blade. Thus fluid is dispersed through only one slot at a time.
It is thus desirable to provide a surgical saw blade with an irrigation system that ensures uniform irrigation of a cutting site without clogging of the irrigation paths, and an irrigating saw blade that can be easily manufactured.